This invention relates generally to binders for holding a plurality of looseleaf sheets together in collated condition to form a bound booklet or the like and more particularly to binders of the type commonly known as flexible post binders.
In construction, flexible post binders comprise at least one compression slide mechanism which generally includes an elongated channel member and a pair of compressor members slidably mounted on the channel member. In its bottom located near each end, the channel member has at least one hole for receiving one end of a flexible resilient post which also passes through aligned holes in the collated looseleaf sheets. These ends of the posts are bent over to lie within the channel and are held in this bent-over condition by the compressor members operatively positioned along the channel to overlie the bent-over post ends. Each compressor member is moved between its respective operative and inoperative position simply by sliding it along the channel member. The other end of each post suitably engages the opposite side of the collated sheets. For instance, the other end of each post may be equipped with an enlarged head having a diameter larger than the diameter of the post receiving holes in the collated sheets. With such an arrangement, the looseleaf sheets are held tightly together between the head on one side and the channel member on the other side by the interconnecting post. In place of a headed post, another slide compression mechanism may be utilized. In the latter instance, the head is not necessary inasmuch as both ends of each post are held in bentover condition by their respective compressor members with the looseleaf sheets bound tightly together between the two channel members by the interconnecting posts.
In addition to providing a simple and convenient means of binding looseleaf sheets together, flexible post binders of the type described may also be utilized to store the bound looseleaf sheets in suspension-type filing cabinets or racks. For this purpose, each compressor member is formed with a hook portion at its outer end. With the compressor members in their operative position overlying the respective bent-over post ends, this hook portion extends outwardly beyond the end of the channel member; and, in this position, the bound looseleaf sheets may be hung or on suspended spaced on parallel support rods with which the filing cabinet or rack is equipped.
Both regular (non-suspension type) and suspension-type flexible post binders (i.e. ones having compressor members equipped wih hook portions) are equipped wih a means for limiting the outward movement of the compressor member. With suspension-type binders movement of the compressor members is limited so that only the hook portion is permitted to extend beyond the end of the channel leaving the remaining or compression portion of the compressor member engaging the channel to perform its intended function of holding the posts in bent-over condition which is necessary to maintain the looseleaf sheets in bound condition. With regular or non-suspension type binders, outward movement of the compressor members must be limited so that the compressor members do not fall out of the channel during use. Also, with any flexible post binder, the outer limit of movement is generally made to coincide with the optimum operative position of the compressor member (i.e. the position where satisfactory compressive force is exerted on the bent-over post ends for all post positions). Thus the user is provided with a readily ascertainable operating position; it being only necessary to slide the compressor members outward as far as possible.
One type of motion limiting means is disclosed in copending and commonly assigned U.S. patent application Ser. No. 84,703, filed Oct. 28, 1970. There, the ends of the side rails of the channel member are turned inward toward each other to provide a restriction of the channel. The compressor members which are mounted internally of the channel are constructed such that the hook portions thereof may pass freely between the inturned ends of the channel while the compression portions thereof are prevented from passing therebetween.
Another type of motion limiting means is disclosed in U.S. Pat. No. 3,628,877. There, the compressor member, which is slidably mounted on the channel externally thereof, engages stops or lugs which project externally from the channel to limit its outward movement. These stops or lugs are located externally at the juncture between the side rails and the channel bottom.
Still another type of motion limiting means is disclosed in French Pat. No. 2,089,324. In this patent, tiny pimples or lugs are formed in the top surface of the channel rails. The compressor member, as in U.S. Pat. No. 3,628,877, is externally mounted on the channel and is provided with mating dimples or recesses on its undersurface which engage the lugs on the channel rails thereby limiting outward movement of the compressor member relative to the channel.
The present invention provides a novel and unobvious motion limiting means for flexible post binders which is simpler in construction, easier to produce and more dependable in operation than the motion limiting devices utilized in heretofore known flexible post binders.